posted by Anonymous .
A stone propelled from a catapult with a speed of 50m/s attains a height of 100m.Calculate:(a)the time of flight?
Just as long as anything else that goes up 100 meters and falls
Which is twice as long as it takes to fall 100 meters
h = (1/2) g t^2
100 = 4.9 t^2
t = 4.52 seconds to fall
so about 9 seconds